<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .c1{
            background-color: red;
            width: 200px;
            height: 80px;
            /* 左浮动 */
            float: left;
        }
        .c2{
            background-color: orange;
            width: 220px;
            height: 85px;

            margin-left: 20px;

            float: left;
        }
        .c3{
            background-color: orangered;
            width: 240px;
            height: 90px;
            float: left;
        }
        .c4{
            background-color: greenyellow;
            width: 250px;
            height: 95px;
            
            /* 技巧 */
            clear: both;
        }
    </style>
</head>
<body>
    <div class="c1">
        c1...
    </div>
    <div class="c2">
        c1...
    </div>
    <div class="c3">
        c1...
    </div>
    <div class="c4">
        c1...
    </div>
</body>
</html>